Figure 17 shows the number of people diagnosed with sexually transmitted infections (STIs) in the UK during 2017 - Edexcel - GCSE Biology - Question 9 - 2022 - Paper 1

To calculate the total number of people diagnosed with chlamydia, we can use the following formula:

Using the given values, we substitute:

Thus, the total number of people diagnosed with chlamydia in the UK in 2017 is 244,200.

Chlamydia can be described as a communicable disease because it can be transmitted from one person to another through sexual contact.

One way to prevent the transmission of chlamydia is by using condoms during sexual intercourse.

Chlamydia can be treated with antibiotics because it is caused by the bacterium Chlamydia trachomatis, which is susceptible to antibiotic treatment. Antibiotics work by targeting the bacteria to inhibit their growth and reproduction, effectively clearing the infection from the body.

When a person is infected by bacteria, the immune system responds in several stages:

1. Recognition: Antigens from the bacteria are detected by white blood cells, particularly phagocytes, which engulf and digest the bacteria.

2. Activation: As the white blood cells are activated, they multiply, increasing the number of immune cells available to fight the infection.

3. Antibody Production: Along with phagocytes, B lymphocytes produce specific antibodies that bind to the bacterial antigens, marking them for destruction.

4. Memory: After the initial infection is overcome, memory lymphocytes remain in the body, providing quicker and stronger responses if the same bacteria invade again.